The present invention relates to a process for the preparation of a hydrogen-rich gas carried out by transforming a carbon monoxide-containing gas with steam according to the water-gas shift reaction EQU CO+H.sub.2 O.fwdarw.CO.sub.2 +H.sub.2
This conversion, which constitutes an important part in most of the industrial processes for the preparation of hydrogen, is generally effected in two steps in the presence of a catalyst. The first conversion step, which is performed at a temperature of over 300.degree. C., is known as water-gas shift reaction at elevated temperature. In the second conversion step, the water-gas shift reaction at low temperature, a temperature below 300.degree. C. is used. As most of the catalyst proposed hitherto for the water-gas shift reaction are only sufficiently active in a fairly limited temperature range, it is customary to use different catalysts in each of the two conversion steps as mentioned above.
It has now been found that certain spinels are excellent catalysts for the water-gas shift reaction both in low and high temperature operations. One such catalyst is described in U.S. Pat. No. 4,166,101 where the spinel has the formula Cu.sub.0.5 Zn.sub.0.5 Fe.sub.2 O.sub.4.